PREFACE 



THE general aim of the book is to present to senior students 

 and investigators the results of recent work in a few of 

 those branches of plant physiology which are at present 

 attracting attention. Matter already to be found in text- 

 books has been almost entirely excluded. 



In order to preserve to some extent a historical method 

 of treatment, the date is inserted after the name of each 

 worker, and is followed by a numeral to show to which 

 paper reference is being made in cases where more than 

 one were published in a year. 



By such a presentation of portions of the science which 

 are still in a state of rapid growth, it is hoped that further 

 investigation will be stimulated. The choice of material 

 by the author was, to a considerable degree, influenced 

 by his familiarity with certain subjects of general interest, 

 portions of which are being studied experimentally by 

 the staff of the School of Botany, Trinity College, Dublin. 

 Upon these, rather than upon other researches of equal 

 or greater importance, he has felt qualified to write, on 

 account of his first-hand knowledge of many of the methods 

 employed. A small amount of hitherto unpublished work 

 has also been included. 



Throughout the book quantitative data have been 



v 



35SS38 



